Many consumers choose to use the email service provided by their internet service providers (ISPs). The ISPs could provide one or more internet services to the consumer, including asymmetrical digital subscriber line (ADSL), cable, mobile, 3G, and/or long-term evolution (LTE). The customer's choice is often driven by: (i) convenience; (ii) ignorance of the ISP type (e.g., cloud email services); (iii) trust in the customer's ISP; and/or (iv) lack of trust of cloud-based service providers. ISPs may also provide additional security controls that protect the end users from external unsolicited bulk messages (SPAM) or viruses.
State of the art email services provide automatic filtering services with the objective of improved usability for registered users. Filtering may depend on rules or heuristics based on the content of the email body, content of header(s), and/or reputation metrics.